[codex] Make Core AI Lab macOS-only

[rudrankriyam]

What changed

• remove the iOS app and iOS test targets, including their target-only Xcode project objects
• rename the surviving macOS targets to CoreAILab and CoreAILabTests
• keep one shared CoreAILab scheme and remove the old CoreAILabMac scheme
• rename the macOS bundle identifiers to match the canonical target names
• update the README, agent guide, macOS CI workflow, and diarization integration runner

Why

Core AI Lab is a macOS app. Removing the duplicate iOS app graph makes the checked-in Xcode project reflect that product truth and leaves one unambiguous app scheme. The separate opt-in physical iOS device harness remains available for framework behavior checks.

Impact

Developers and CI should use the CoreAILab scheme. The macOS app product remains CoreAILab.app, while its target and test bundle no longer carry the Mac suffix.

Validation

• xcodebuild -version — Xcode 27.0 (27A5209h)
• xcodebuild -project CoreAIFrameworkLab.xcodeproj -list -json -disableAutomaticPackageResolution -skipPackageUpdates — only CoreAILab and CoreAILabTests, with one CoreAILab scheme
• macOS CoreAILab build — passed
• macOS CoreAILab build-for-testing — passed and produced CoreAILab_macosx27.0-arm64.xctestrun with CoreAILabTests
• Swift contract suite with the local Xcode-path verifier skipped — 289 tests across 33 suites passed
• focused Core AI fixture rerun — passed
• python3 -m unittest discover -s Scripts/tests -p 'test_*.py' — 43 tests passed

The skipped export verifier hardcodes /Applications/Xcode-beta.app, which is the documented CI runner path but is not present on this machine; the active local Xcode is /Applications/Xcode-27.0.0-Beta.2.app.